Digital images are made up of individual picture elements (pixels) each of which may contain information regarding color, hue, intensity and location. Gray scale images contain pixels with luminosity values. For example, eight bit gray scale image pixels can have luminosity values from zero to 255.
Digital image images may be processed to extract useful information. For example, it is well known in the art to scan a text document and process the scanned image for text and to recognize the text characters and convert the image into a text document. It is also known in the art to separate text areas in a scanned image from pictures and graphical elements.
Sometimes, however, a scanned image presents significant problems for a computer to determine where a desired feature is because of low contrast or noise in the image. Various methods are known in the art to enhance digital images, such as by contrast enhancement or sharpening. Many digital imaging processing techniques look for edges of objects within an image. It is often as useful to know where edges are not present so as to limit further image processing to areas in which edges of objects within the image filed may in fact be present.
What is needed is a reliable method of determining edgeless areas in a digital image.